HTRC110 communication

[BLaz1]

Hello everyone,
I'm trying to read HITAG card serial number (UID), I'm using HTRC11001t. Problem is that I don't know which command to send from uC. I've read datasheet for HTRC110 and application note, but I still don't understand how communication works (I am totally unexperienced with the subject and this is my first work assignment on my job). If I send 111----- for entering READ TAG mode, what should I do next in order to get card's serial number? I'm not interested in using crypto mode or any advanced options, just need to simply read serial number. If someone would tell me, or at least refer me to some other link or document that explains protocol with htrc, I would be very greatful.

 

[bigdogguru]

Reference:, Section: 9.7 Reading out the digital data, Page: 46

9.7 Reading out the digital data

The demodulated and digitized data is read out via DOUT.
First, an interface reset condition has to be applied as
usual before all serial commands [1]. After this, the three-bit
command READ_TAG is issued. After sending
the last of the three bits (1’s), the
HTRC110 switches instantly to transparent mode.
So, the transponder data is directly presented at
DOUT with a delay from RX to DOUT depending
on the demodulator filter settings. For optimizing the
WRITE-pulse positions (see Section 10.2 “Driver-off period
width and position”) the delay times of 310μs for FILTERL=0
and 175μs for FILTERL=1 shall be considered.

SCLK shall be low during that transparent
mode. The transparent READ_TAG mode is
terminated by a low to high transition of SCLK.

Implementing a quasi-SPI interface which could receive the transponder data with the SCLK line held low during transmission would most likely be the direct method.

A schematic of the current design would be helpful in advise you further.

BigDog

 

[BLaz1]

Ok, thank you, but I still don't understand which command (or commands) should I send from uC in order to get card's UID.

 

[bigdogguru]

You are sending the correct command, READ_TAG, however once the command is received the device enters transparent mode which automatically reads compatible transponders and remains in that mode as long as SCLK remains low.

When in transparent mode the device automatically reads any compatible transponders and outputs the RFID data on DOUT as outlined in the datasheet.

Note, SCLK must remain low or another READ_TAG command must be issued to return the device back to transparent mode.


BigDog

 

[BLaz1]

Ok, but if I enter READ TAG and if I'm getting some data from DOUT (some array of 1s and 0s), how do I know what it represents? As I wrote, I wan't to read HITAG card's serial number. If I have some data on DOUT, how can I be sure that it is serial number and not some other data?